The just-released PlayStation Vita port of Earth Defense Force 2017 is now officially confirmed for a North American release as well, via D3 Publisher's official Facebook page for the game (via Joystiq). The Vita port of the previously Xbox 360-exclusive third-person action game was confirmed only recently for a fall 2012 release in Japan, but D3 Publisher avoided confirmation of any wider release until now.
There's not much more to go on at the moment. Taking a peek at the series' official Twitter feed reveals that a version of the game is coming to Europe as well. The port should be landing outside of Japan sometime this "winter," which presumably means early 2013. We'll keep you posted as more details emerge.